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  Subjects -> CHEMISTRY (Total: 845 journals)
    - ANALYTICAL CHEMISTRY (50 journals)
    - CHEMISTRY (596 journals)
    - CRYSTALLOGRAPHY (22 journals)
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ANALYTICAL CHEMISTRY (50 journals)

Showing 1 - 50 of 50 Journals sorted alphabetically
Accounts of Chemical Research     Full-text available via subscription   (Followers: 99)
Acta Analytica     Hybrid Journal   (Followers: 7)
Advances in Analytical Chemistry     Open Access   (Followers: 28)
American Journal of Analytical Chemistry     Open Access   (Followers: 31)
Analytica Chimica Acta     Hybrid Journal   (Followers: 38)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 28)
Analytical Chemistry     Full-text available via subscription   (Followers: 251)
Analytical Chemistry Insights     Open Access   (Followers: 22)
Analytical Chemistry Research     Open Access   (Followers: 7)
Analytical Letters     Hybrid Journal   (Followers: 11)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 10)
Annual Review of Analytical Chemistry     Full-text available via subscription   (Followers: 9)
Biomonitoring     Open Access   (Followers: 2)
Chemical Data Collections     Hybrid Journal  
Chinese Journal of Analytical Chemistry     Full-text available via subscription   (Followers: 3)
Combinatorial Chemistry - an Online Journal     Open Access   (Followers: 2)
Composites Communications     Full-text available via subscription  
Comprehensive Analytical Chemistry     Full-text available via subscription   (Followers: 5)
Critical Reviews in Analytical Chemistry     Hybrid Journal   (Followers: 26)
Current Analytical Chemistry     Hybrid Journal   (Followers: 7)
Drug Testing and Analysis     Hybrid Journal   (Followers: 6)
Electroanalysis     Hybrid Journal   (Followers: 6)
Field Analytical Chemistry and Technology     Hybrid Journal   (Followers: 4)
Handbook of Analytical Separations     Full-text available via subscription   (Followers: 1)
Handbook of Thermal Analysis and Calorimetry     Full-text available via subscription   (Followers: 1)
International Journal of Analytical Chemistry     Open Access   (Followers: 21)
International Journal of Chemical and Analytical Science     Full-text available via subscription   (Followers: 3)
International Journal of Environmental Analytical Chemistry     Hybrid Journal   (Followers: 6)
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 7)
Journal of Analytical & Bioanalytical Techniques     Open Access   (Followers: 6)
Journal of Analytical Atomic Spectrometry     Full-text available via subscription   (Followers: 10)
Journal of Analytical Chemistry     Hybrid Journal   (Followers: 20)
Journal of Combinatorial Chemistry     Full-text available via subscription  
Journal of Electroanalytical Chemistry     Hybrid Journal   (Followers: 5)
Journal of Essential Oil Research     Hybrid Journal   (Followers: 2)
Journal of Radioanalytical and Nuclear Chemistry     Hybrid Journal   (Followers: 5)
Journal of Thermal Analysis and Calorimetry     Hybrid Journal   (Followers: 23)
Main Group Metal Chemistry     Hybrid Journal   (Followers: 1)
Microchemical Journal     Hybrid Journal   (Followers: 3)
Nigerian Journal of Chemical Research     Full-text available via subscription  
Phytochemical Analysis     Hybrid Journal   (Followers: 2)
Polish Journal of Chemical Technology     Open Access   (Followers: 1)
Reviews in Analytical Chemistry     Hybrid Journal   (Followers: 9)
Sample Preparation     Open Access  
Surface and Interface Analysis     Hybrid Journal   (Followers: 14)
Techniques and Instrumentation in Analytical Chemistry     Full-text available via subscription   (Followers: 5)
TrAC Trends in Analytical Chemistry     Full-text available via subscription   (Followers: 52)
Trends in Environmental Analytical Chemistry     Hybrid Journal   (Followers: 2)
Vibrational Spectroscopy     Hybrid Journal   (Followers: 13)
World Journal of Analytical Chemistry     Open Access   (Followers: 1)
Journal Cover Journal of Analytical Chemistry
  [SJR: 0.268]   [H-I: 23]   [20 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1608-3199 - ISSN (Online) 1061-9348
   Published by Springer-Verlag Homepage  [2341 journals]
  • Electrochemical methods for the determination of heparin
    • Authors: D. A. Vishenkova; E. I. Korotkova
      Pages: 349 - 353
      Abstract: Abstract A review of studies on the determination of heparin in various samples (pharmaceuticals, biological fluids) by electrochemical methods of analysis in 1976–2014 is presented. Heparin is most often determined in pharmaceuticals by polarography using cationic dyes, and in biological samples, by differential pulse methods on non-stationary mercury electrodes. Works on the creation of heparin-selective electrodes coated with a polyvinylchloride membrane with quarternary ammonium salts are most promising; they can, probably, be used for the creation of portable devices for the determination of heparin.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040153
      Issue No: Vol. 72, No. 4 (2017)
       
  • Enzymeless determination of cholesterol using gold and silver
           nanoparticles as electrocatalysts
    • Authors: A. V. Okhokhonin; S. Yu. Saraeva; A. I. Matern; A. N. Kozitsina
      Pages: 354 - 361
      Abstract: Abstract We present the results of synthesis and study of the electrocatalytic activity of gold and silver nanoparticles of different composition (individual metals, core–shell particles, nanoalloys, and particles synthesized electrochemically), immobilized on the surface of a glassy carbon electrode, with respect to cholesterol. A surfactant (cetyltrimethylammonium bromide) is selected to create an aqueous–organic emulsion of cholesterol. It is demonstrated that nanoparticles with a gold core and a silver shell with the regression equation of I = 1.4 × 10–5 c chol + 5.8 × 10–5 (R 2 = 0.97) and silver nanoparticles synthesized electrochemically with the regression equation of I = 1.0 × 10–5 c chol + 3.0 × 10–4 (R 2 = 0.95) possess optimal electrocatalytic characteristics.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040116
      Issue No: Vol. 72, No. 4 (2017)
       
  • Surface modification of electrodes by carbon nanotubes and gold and silver
           nanoparticles in monoaminoxidase biosensors for the determination of some
           antidepressants
    • Authors: E. P. Medyantseva; D. V. Brusnitsyn; R. M. Varlamova; A. A. Maksimov; O. A. Konovalova; H. C. Budnikov
      Pages: 362 - 370
      Abstract: Abstract Surface modification of screen-printed graphite electrodes with nanostructured materials (multiwall carbon nanotubes, gold and silver nanoparticles) allow their application as supports of amperometric monoaminoxidase biosensors for the determination of antidepressant drugs (moclobemide, tianeptine, and amitriptyline). This approach improves analytical characteristics of the corresponding biosensors because of the inhibitory effect of antidepressants (two-parameter concerted inhibition) on the catalytic activity of an immobilized enzyme. The analytical capabilities of the developed biosensor types were compared. The range of working concentrations was from 5 × 10–9 to 1 × 10–4 M and the lower limit of the analytical range was of about 8 × 10–10 M. Biosensors based on electrodes modified with nanostructured materials were tested in the control of the concentration of drugs in body fluids (urine) and dosage forms.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040086
      Issue No: Vol. 72, No. 4 (2017)
       
  • Nonenzymatic determination of glucose on electrodes prepared by directed
           electrochemical nanowire assembly (DENA)
    • Authors: K. G. Nikolaev; S. S. Ermakov; A. Offenhäusser; Yu. Mourzina
      Pages: 371 - 374
      Abstract: Abstract The analytical characteristics of gold nanowires prepared by direct electrochemical synthesis were studied with the use of the amperometric determination of glucose as an example. The applicability of the gold nanowires to the determination of glucose in a neutral medium (a phosphate buffer solution with pH 7.2) over a concentration range from 1 × 10–4 to 5 × 10–3 M at a detection potential of +0.35 V was shown. It was found that the sensitivity of a nonenzymatic sensor for the determination of glucose on the gold nanowires was high: 3.7 × 10–4 A M–1 m–2. The limit of detection was 3.3 × 10–5 M.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040104
      Issue No: Vol. 72, No. 4 (2017)
       
  • An electrochemical aptasensor for cytochrome C, based on pillar[5]arene
           modified with Neutral Red
    • Authors: V. B. Stepanova; D. N. Shurpik; V. G. Evtyugin; I. I. Stoikov; G. A. Evtyugin; T. Gianik
      Pages: 375 - 381
      Abstract: Abstract An electrochemical aptasensor is developed for the highly sensitive determination of cytochrome C, using a change in the redox current of Neutral Red covalently bound to terminal carboxyl groups of decasubstituted pillar[5]arene as a signal. The inclusion of the analyte into the complex with an aptamer reduces peaks of redox current of the dye through the dissociation of electron transfer chain in the surface layer. The aptasensor enables the determination of 1 nM to 1.0 mM of cytochrome C in the presence of 1000-fold excesses of albumin, polyethylene glycol, and lysozyme as models of interfering components in biological fluids.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040141
      Issue No: Vol. 72, No. 4 (2017)
       
  • Chronoamperometric evaluation of the antioxidant capacity of tea on a
           polyquercetin-modified electrode
    • Authors: G. K. Ziyatdinova; E. V. Kozlova; H. C. Budnikov
      Pages: 382 - 389
      Abstract: Abstract It was established that the components of tea are oxidized on a glassy carbon electrode modified with carbon nanotubes and electropolymerized quercetin in a phosphate buffer solution (pH 7.0) as a supporting electrolyte under conditions of differential pulse voltammetry. The oxidation potentials of the individual phenolic antioxidants of tea (gallic acid, rutin, quercetin, catechin, epigallocatechin gallate, and tannin) on the modified electrode were found. A method for the chronoamperometric determination of the antioxidant capacity (AOC) of tea was developed based on the oxidation of tea antioxidants at a potential of 0.20 V. The AOC of tea was evaluated using а difference between the oxidation currents of the analyte and a supporting electrolyte after 50 s of electrolysis in terms of gallic acid. The analytical range of gallic acid was 0.25‒750 μM with a detection limit of 0.063 μM. Positive correlations of the AOC with antioxidant activity in a reaction with 2,2-diphenyl-1-picrylhydrazyl and the total phenolic content were found (r = 0.700 and 0.647 at r crit = 0.396, respectively).
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040189
      Issue No: Vol. 72, No. 4 (2017)
       
  • Determination of the surface area of loose metal deposits by impedance
           spectroscopy
    • Authors: V. S. Nikitin; V. M. Rudoi; T. N. Ostanina; E. A. Dolmatova
      Pages: 390 - 395
      Abstract: Abstract The surface area and fractal dimensions of the surface of loose copper and zinc deposits obtained within 30 and 300 s at direct current sixfold exceeding limiting diffusion current on a smooth electrode were in situ determined by impedance spectroscopy. Impedance measurements were performed in 0.5 M Na2SO4 solution. A constant phase element taking into account the distribution of double-layer capacitance over the fractal surface of the electrode was used in the equivalent impedance scheme. Specific surface calculated with regard to the weight of the released metal slightly varied within 300 s (from 6.16 to 6.55 and from 7.12 to 5.89 m2/g for copper and zinc deposits, respectively). Fractal dimensions estimated by chronopotentiometry were given for comparison. Fractal dimensions found by two methods for loose copper and zinc deposits agree with each other; their values (2.19–2.75) testify that the surface of the deposits densely fills the space.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040098
      Issue No: Vol. 72, No. 4 (2017)
       
  • Voltammetric determination of Tartrazine in food
    • Authors: O. I. Lipskikh; A. A. Nikolaeva; E. I. Korotkova
      Pages: 396 - 401
      Abstract: Abstract A possibility of using voltammetry for the direct determination of yellow synthetic food dye Tartrazine, included in the list of substances regulated in food, is demonstrated. The electrochemical behavior of the dye is studied by direct current voltammetry using a glassy carbon electrode. It is shown that the signal of Tartrazine electrochemical reduction is the most pronounced in an acidic medium at pH 2.0, accumulation potential of 0.1 V, and time of 10 s. The dependence of the electrochemical reduction current of the dye at a potential of–0.25 V on its concentration is linear in the range 0.05–0.50 mg/L with the determination limit 0.034 mg/L and detection limit 0.011 mg/L. A procedure for quantifying the dye in food is proposed.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040062
      Issue No: Vol. 72, No. 4 (2017)
       
  • Voltammetric identification of insulin and its analogues using glassy
           carbon electrodes modified with polyarylenephthalides
    • Authors: R. A. Zil’berg; Yu. A. Yarkaeva; E. I. Maksyutova; A. V. Sidel’nikov; V. N. Maistrenko
      Pages: 402 - 409
      Abstract: Abstract Using chemometrics, we developed a voltammetric method for the identification and discrimination of pharmaceuticals containing insulin and its analogues from various manufacturers. Their electrochemical behavior on glassy carbon electrodes modified with polyarylenephthalide films is studied; analytical characteristics are evaluated; and the optimal conditions for recording the analytical signal and the nature of electrode processes are determined. Some examples of the voltammetric identification and recognition of pharmaceutical products containing insulin are given.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040177
      Issue No: Vol. 72, No. 4 (2017)
       
  • Polymer matrices with molecular memory as affine adsorbents for the
           determination of myoglobin as a cardiac marker of acute myocardial
           infarction by voltammetry
    • Authors: V. V. Shumyantseva; T. V. Bulko; L. V. Sigolaeva; A. V. Kuzikov; A. I. Archakov
      Pages: 410 - 414
      Abstract: Abstract A possibility of myoglobin determination using screen-printed graphite electrodes modified with a poly(o-phenylenediamine)-based molecularly imprinted polymer (MIP) obtained by the electropolymerization of o-phenylenediamine monomer molecules on the surface of a screen-printed graphite electrode in the presence of myoglobin template molecules is considered. It is shown that the conjugation of MIP with multiwall carbon nanotubes (MWCNT) results in an increase in the sensitivity of the MIP-biosensor in the electrochemical determination of myoglobin by the direct registration of the reduction peak of hemoprotein Fe3+ by square wave voltammetry on screen-printed graphite electrodes modified with MWCNT/MIP and MIP. Equilibrium dissociation constants K d for the interaction of myoglobin with MWCNT/MIP- and MIP-electrodes, which equaled (9.8 ± 2.6) × 10–11 and (2.4 ± 0.5) × 10–8 M, respectively, are calculated. It is shown that the sensitivity of the electrochemical MWCNT/MIP-biosensor for myoglobin determination (1.5 × 10–2 A/nmol of myoglobin) is higher than that of the MIP-biosensor (2.0 × 10–4 A/nmol of myoglobin).
      PubDate: 2017-04-01
      DOI: 10.1134/s106193481704013x
      Issue No: Vol. 72, No. 4 (2017)
       
  • Study of the antioxidant activity and total polyphenol concentration of
           medicinal plants
    • Authors: A. V. Ivanova; E. L. Gerasimova; E. R. Gazizullina; K. G. Popova; A. I. Matern
      Pages: 415 - 420
      Abstract: Abstract Infusions of medicinal plants are investigated by potentiometry using a system of K3[Fe(CN)6]/K4[Fe(CN)6]. Models of some flavonoids, phenol carbonic acids, ascorbic acid, and their mixtures are studied. The total polyphenol concentration in these samples is determined by the Folin–Ciocalteu method. Dependences of antioxidant activity on extraction time are obtained.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040049
      Issue No: Vol. 72, No. 4 (2017)
       
  • Potentiometric sensors based on new active components in the multisensor
           determination of homologues anionic surfactants
    • Authors: N. M. Makarova; E. G. Kulapina
      Pages: 421 - 429
      Abstract: Abstract Potentiometric sensors are proposed on the basis of alkyl sulfates and cationic copper(II) complexes with organic reagents selective to anionic surfactants. Physical and chemical properties of the ionophores (composition, thermal stability, solubility) are determined in aqueous solutions and in the membrane phase. The studied compounds are poorly soluble (K s = n × 10–22–n × 10–20) and thermally stable at 80−90°C. The main electroanalytical properties of sensors are estimated, i.e., analytical range in solutions of sodium alkyl sulfates 2 × 10–7–1 × 10–2 M; 46 <α < 66 mV/рc; LOD = 1 × 10–7 M; response time 8–9 s in a solution of sodium dodecyl sulfate with the concentration not lower than 1 × 10–4 M; potential drift 2–3 mV/day; and lifetime 12 months. The multisensor determination of homologues sodium alkyl sulfates in model mixtures and natural waters is performed using the proposed sensors.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040074
      Issue No: Vol. 72, No. 4 (2017)
       
  • Application of the localized surface plasmon resonance of gold
           nanoparticles for the determination of 1,1-dimethylhydrazine in water:
           Toward green analytical chemistry
    • Authors: Ali Reza Zarei; Farideh Barghak
      Pages: 430 - 436
      Abstract: Abstract Localized surface plasmon resonance (LSPR) is an optical phenomena generated by light when it interacts with conductive nanoparticles that are smaller than the incident wavelength. In this work, we proposed a simple, fast, and green method for spectrophotometric determination of unsymmetrical 1,1-dimethylhydrazine (UDMH) based on LSPR property of gold nanoparticles (AuNPs). An LSPR band is produced via reduction of Au3+ ions in solution by UDMH as active reducing agent in the presence of cetyltrimethylammonium chloride as a capping agent. Some important parameters in the formation of LSPR including Au(III) concentration, pH, concentration of stabilizer, and reaction time were studied and optimized. Under optimum conditions, the LSPR intensity displays linear response with the increasing UDMH concentration in the range from 0.5–10 μg/mL at 550 nm with a detection limit of 0.2 μg/mL. Also, the relative standard deviation for ten replicate determination of 5.0 μg/mL of UDMH was 3%. Usage of AuNPs as new nontoxic reagent instead of hazardous reagents in the spectrophotometric determination of UDMH is a step toward green analytical chemistry. The proposed method was successfully applied for determination of UDMH in water and wastewater samples.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040025
      Issue No: Vol. 72, No. 4 (2017)
       
  • Adenosine triphosphate detection by controlled-release of carboxy
           fluorescein from mesoporous silica nanoparticles blocked with
           aptamer-based gold nanoparticles
    • Authors: Xiaoting Ji; Haoyuan Lv; Wei Zhang; Caifeng Ding
      Pages: 437 - 444
      Abstract: Abstract In this paper, an adenosine-5′-triphosphate (ATP) controlled-release strategy to construct a fluorescence sensing platform has been designed. In the sensing platform, because of ATP aptamer and singlestranded DNA (ssDNA)-linked mesoporous silica nanoparticles (Si-MPs) were hybridized, the pores of Si-MPs were blocked with Au nanoparticles (AuNPs) modified with ATP aptamer. Carboxy fluorescein was plugged in channels of Si-MPs. In the presence of target molecule ATP, the ATP aptamer combined with ATP and the AuNPs got away from the pore of the surface of Si-MPs modified by ssDNA. 5-Carboxyfluorescein molecule was released to allow the fluorescent detection. By monitoring the fluorescence at 518 nm, ATP could be quantitatively detected with a detection limit of 6 × 10–8 M. The linear response range was 6 × 10–8 to 1 × 10–6 M. This assay was also able to discriminate ATP from its analogs. The controlled-release aptamer-based biosensor could have an effective application in human breast cancer MCF-7 cells.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040165
      Issue No: Vol. 72, No. 4 (2017)
       
  • Lactose tailored boronic acid conjugated fluorescent gold nanoclusters for
           turn-on sensing of dopamine
    • Authors: J. S. Anjali Devi; B. Aswathy; Sasidharan Asha; Sony George
      Pages: 445 - 459
      Abstract: Abstract Dopamine being a neurotransmitter and chemical messenger plays a vivacious role in a number of significant medical conditions like Parkinson’s disease, Attention Deficit Hyperactivity Disorder, Schizophrenia, and drug addiction. As turn-on sensors have a superior level of selectivity than fluorescence quenching based sensors, we developed a fluorescence retrieval strategy for dopamine sensing. Here, highly fluorescent amino phenyl boronic acid (APBA)‒conjugated gold nanocluster (Au‒BSA‒APBA probe) has been synthesised from bovine serum albumin‒protected gold nanocluster (Au‒BSA NCs). Boronic acid forms boronate ester with disaccharides such as lactose due to its affinity to polyols. Hence fluorescence of Au‒BSA‒APBA probe is quenched when it binds with lactose molecules through boronate ester formation. The fluorescence of Au‒BSA‒APBA‒lactose system can be retrieved (turn-on) with dopamine by the competitive displacement of lactose from the probe surface which suggests the higher affinity of boronic acid to the catechol group of dopamine. Furthermore, real samples spiked with dopamine including human serum and urine were analysed using this turn-on sensor and showed excellent recovery percentage. The developed fluorescent sensor offered high selectivity for dopamine over other catecholamines and aminoacids with detection limit as low as 0.7 μM.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040037
      Issue No: Vol. 72, No. 4 (2017)
       
  • Size-exclusion liquid chromatography of poly( N -vinylformamide)s in
           aqueous solutions
    • Authors: V. D. Krasikov; N. I. Gorshkov; I. I. Malakhova; O. S. Egorova; Yu. V. Pokhvoshchev
      Pages: 460 - 467
      Abstract: Abstract The exclusion mechanism of the separation of poly(N-vinylformamide) and its derivatives with a cysteamine terminal group in gel permeation chromatography implemented by the suppression of polyelectrolyte swelling and the electroexclusion of macromolecules was established by the transport analytical methods of molecular hydrodynamics (HPLC, velocity sedimentation, and intrinsic viscosity). Based on an analysis of the hydrodynamic characteristics and molecular weights of polymer fractions determined by velocity sedimentation, it was found that the molecular characteristics and polydispersity of the water-soluble poly(N-vinylamide) s of aliphatic carboxylic acids and their derivatives can be calculated with the use of the Benoit universal calibration dependence.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817040050
      Issue No: Vol. 72, No. 4 (2017)
       
  • Chromatographic determination of nitrophenols in aqueous media after
           two-stage preconcentration using an N-vinylpyrrolidone-based polymer
    • Authors: P. T. Sukhanov; A. A. Kushnir; E. V. Churilina; N. V. Maslova; G. V. Shatalov
      Pages: 468 - 472
      Abstract: Abstract Two-stage procedures for the preconcentration of nitrophenols (4-nitrophenol, 2,4- and 2,5-dinitrophenol, and 2,4,6-trinitrophenol) from aqueous solutions are proposed. At the first stage, the preconcentration and desorption of nitrophenols under dynamic conditions is carried out. At the second stage, depending on the nature of the desorption solution, the eluate is evaporated (acetonitrile) or saturated with ammonium sulfate and extracted with acetone (aqueous NH3 solution). The concentration factors are 4000 and 910, respectively. Nitrophenols are determined in concentrates by thin layer chromatography and HPLC, the limits of detection are 1.0–1.8 and 0.25–0.45 μg/L, respectively. The duration of analysis is 200 min.
      PubDate: 2017-04-01
      DOI: 10.1134/s1061934817020137
      Issue No: Vol. 72, No. 4 (2017)
       
  • Headspace gas chromatographic determination of 1,4-dioxane with adsorption
           preconcentration on silica modified with λ-carrageenan
    • Authors: O. I. Fedorchuk; N. G. Kobylinska; V. N. Zaitsev
      Pages: 295 - 302
      Abstract: Abstract Organosilica materials containing λ-carrageenan on their surface are synthesized. The conditions for the immobilization of the polysaccharide, such as phase contact time and pH and concentration of solutions, are optimized. It is shown that the chemisorption of the polysaccharide passes through ion exchange multipoint immobilization, which provides a high hydrolytic stability of the prepared organosilica. The rate of washing of λ-carrageenan to the solution does not exceed 0.5%. The physical and chemical characteristics of the new material are studied. In particular, it is shown that the material is completely stable up to 200°C and reversibly desorbs water at 120°C; it well adsorbs 1,4-dioxane from the gas phase and desorbs it under heating to 70°C. This ensures the use of the prepared carrageenan-containing material as an adsorbent for a solid-phase cartridge designed for the adsorption preconcentration of 1,4-dioxane in its headspace gas chromatographic determination in samples of nonionic surfactants. The developed procedure ensures the determination of 1,4-dioxane by gas chromatography with a flame ionization detector in the concentration range 0.012–3.750 mg/L with a limit of detection of 0.0014 mg/L. Preconcentration lowers the limit of detection in the determination of 1,4-dioxane by 50 times.
      PubDate: 2017-03-01
      DOI: 10.1134/s1061934817010063
      Issue No: Vol. 72, No. 3 (2017)
       
  • Optimization of a method for the determination of a mustard gas biomarker
           in human blood plasma by liquid chromatography–high-resolution mass
           spectrometry
    • Authors: A. V. Braun; I. V. Rybal’chenko; M. A. Ponsov; Ya. V. Stavitskaya; L. A. Tikhomirov; A. P. Grechukhin
      Pages: 303 - 308
      Abstract: Abstract A method for the determination of a mustard gas biomarker (an S-hydroxyethylthioethyl adduct with albumin) in blood plasma was optimized with the use of HPLC with high-resolution tandem mass-spectrometric detection. This method is based on the hydrolysis of this adduct by the proteinase K enzyme with the formation of the following stable tripeptide with cysteine, proline, and phenylalanine: S-[HETE]-Cys- Pro-Phe. The conditions of the sample preparation of human plasma artificially contaminated by mustard gas (the selection of an aliquot portion volume and an enzyme for the hydrolysis), the mass-spectrometric detection (the selection of optimum pairs of ion reactions and high-resolution detection modes), and the gradient elution program in the HPLC separation of an analyzed mixture were optimized. The detection limit of mustard gas in human blood plasma was 1 ng/mL. The approach proposed was tested in the analysis of human blood plasma samples by the standard addition technique and also within the framework of the first official biomedical test carried out by the Organization for the Prohibition of Chemical Weapons (OPCW) in 2016, and it exhibited a good accuracy, reproducibility, and specificity of determination.
      PubDate: 2017-03-01
      DOI: 10.1134/s1061934817030030
      Issue No: Vol. 72, No. 3 (2017)
       
  • Detection and quantification of chitosan aggregates by pressure-assisted
           capillary zone electrophoresis
    • Authors: T. G. Dzherayan; N. G. Vanifatova; A. A. Burmistrov; E. V. Lazareva; A. V. Rudnev
      Pages: 309 - 315
      Abstract: Abstract An approach to the detection and determination of chitosan aggregates in acetic acid solutions is proposed using pressure-assisted capillary zone electrophoresis. Processes of chitosan aggregation are studied depending on the composition of dispersion medium and storage time. The presence of several species of positively charged chitosan aggregates is revealed for the first time. Particle sizes in the range 20–2500 nm are determined by scanning electron microscopy and static and dynamic light scattering. The dependence of the shape of electropherograms on particle size distribution obtained under the same conditions is found. A trend to changing electrophoretic mobility depending on the size of the aggregate is observed, which enables the approximate evaluation of the polydispersity of chitosan solutions. Chitosan is used for the effective dynamic modification of capillaries, which does not require the introduction of a modifier into the background electrolyte.
      PubDate: 2017-03-01
      DOI: 10.1134/s1061934817030042
      Issue No: Vol. 72, No. 3 (2017)
       
 
 
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